Thread can't be seen while replying from mobile

Hi, I can't see a thread I'm replying to while replying from mobile - reply area takes all screen (see the screenshot). It's quite inconvenient as I often want to see original thread or quote something from it. I remember it was different few months ago, before last changes - reply area occupied about half of screen and a thread was seen in other half. It would be nice to have it fixed. Thanks!

P.S. I think it would be nice to have ability to minimize a reply with some button, look at a thread, maximize the reply back and continue replying. Like a normal window on a computer.